#!/usr/bin/env bash

# Copyright (C) 2016 Paul Kocialkowski <contact@paulk.fr>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

SYS_BLOCK_PATH="/sys/class/block"
DEV_PATH="/dev"
DEVICE="device"
VENDOR="vendor"
MODEL="model"
NAME="name"

usage() {
	printf '%s\n' "$executable [action] [storage] [kernel image|kernel modules]" >&2

	printf '\n%s\n' 'Actions:' >&2
	printf '%s\n' '  backup - Backup kernel image' >&2
	printf '%s\n' '  image - Install kernel image' >&2
	printf '%s\n' '  modules - Install kernel modules' >&2

	usage_storage

	printf '\n%s\n' 'Environment variables:' >&2
	printf '%s\n' '  VBOOT_KEYS_PATH - Path to the vboot keys' >&2
	printf '%s\n' '  VBOOT_TOOLS_PATH - Path to vboot tools' >&2
}

usage_storage() {
	printf '\n%s\n' 'Storage:' >&2

	local nodes=$( ls "$SYS_BLOCK_PATH" )
	local node_path
	local name

	for node in $nodes
	do
		node_path="$DEV_PATH/$node"
		if ! [ -b "$node_path" ]
		then
			continue
		fi

		name=$( storage_name "$node_path" )
		if [ -z "$name" ]
		then
			continue
		fi

		printf '%s\n' "  $node_path - $name" >&2
	done
}

storage_affect_confirm() {
	local storage_path=$1

	local name=$( storage_name "$storage_path" )
	local confirm

	printf '%s\n' 'This is going to affect the following storage:'
	printf '%s\n' "  $storage_path - $name"
	printf '%s' 'Press enter to confirm: '

	read confirm
}

storage_name() {
	local storage_path=$1

	local node=$( basename "$storage_path" )
	local vendor_path="$SYS_BLOCK_PATH/$node/$DEVICE/$VENDOR"
	local model_path="$SYS_BLOCK_PATH/$node/$DEVICE/$MODEL"
	local name_path="$SYS_BLOCK_PATH/$node/$DEVICE/$NAME"
	local vendor
	local name

	if [ -f "$model_path" ]
	then
		name=$( cat "$model_path" )
	elif [ -f "$name_path" ]
	then
		name=$( cat "$name_path" )
	else
		return 0
	fi

	name=$( printf '%s\n' "$name" | sed -e "s/^[[:space:]]*//;s/[[:space:]]*$//" )

	if [ -f "$vendor_path" ]
	then
		vendor=$( cat "$vendor_path" )
		vendor=$( printf '%s\n' "$vendor" | sed -e "s/^[[:space:]]*//;s/[[:space:]]*$//" )

		name="$vendor $name"
	fi

	printf '%s\n' "$name"
}

storage_partition_path() {
	local storage_path=$1
	local index=$2

	storage_partition_path="$storage_path$index"

	if ! [ -b "$storage_partition_path" ]
	then
		storage_partition_path="$storage_path""p$index"
	fi

	if ! [ -b "$storage_partition_path" ]
	then
		return 1
	fi

	printf '%s\n' "$storage_partition_path"
}

storage_partition_mount_path() {
	local storage_partition_path=$1

	local storage_partition_mount_path=$( udisksctl info -b "$storage_partition_path"  | grep "MountPoints" | sed "s/.*MountPoints:[[:space:]]*\(.*\)/\1/g" )

	printf '%s\n' "$storage_partition_mount_path"
}

storage_kernel_path() {
	local storage_path=$1

	cgpt find -t kernel "$storage_path" | head -n 1
}

storage_rootfs_path() {
	local storage_path=$1

	cgpt find -t rootfs "$storage_path" | head -n 1
}

backup() {
	local storage_path=$1
	local kernel_image_path=$2

	local storage_kernel_path=$( storage_kernel_path "$storage_path" )

	if [ -z "$storage_kernel_path" ]
	then
		printf '%s\n' "No kernel partition found on storage $storage_path" >&2
		return 1
	fi

	cat "$storage_kernel_path" > "$kernel_image_path"

	printf '\n%s\n' "Backed up kernel image to $kernel_image_path"
}

image() {
	local storage_path=$1
	local kernel_image_path=$2

	local storage_kernel_path=$( storage_kernel_path "$storage_path" )

	if [ -z "$storage_kernel_path" ]
	then
		printf '%s\n' "No kernel partition found on storage $storage_path" >&2
		return 1
	fi

	storage_affect_confirm "$storage_path"

	cat "$kernel_image_path" > "$storage_kernel_path"
	sync

	printf '\n%s\n' "Installed kernel image on storage $storage_path"
}

modules() {
	local storage_path=$1
	local kernel_modules_path=$2

	local storage_rootfs_path=$( storage_rootfs_path "$storage_path" )

	if [ -z "$storage_rootfs_path" ]
	then
		printf '%s\n' "No rootfs partition found on storage $storage_path" >&2
		return 1
	fi

	storage_affect_confirm "$storage_path"

	# Partition may already be mounted.
	udisksctl mount -b "$storage_rootfs_path" || true

	storage_rootfs_mount_path=$( storage_partition_mount_path "$storage_rootfs_path" )

	rsync -a --keep-dirlinks "$kernel_modules_path" "$storage_rootfs_mount_path/"
	sync

	udisksctl unmount -b "$storage_rootfs_path"

	printf '\n%s\n' "Installed kernel modules on storage $storage_path"
}

requirements() {
	local requirement
	local requirement_path

	for requirement in "$@"
	do
		requirement_path=$( which "$requirement" || true )

		if [ -z "$requirement_path" ]
		then
			printf '%s\n' "Missing requirement: $requirement" >&2
			exit 1
		fi
	done
}

setup() {
	root=$(readlink -f "$( dirname "$0" )" )
	executable=$( basename "$0" )

	if ! [ -z "$VBOOT_TOOLS_PATH" ]
	then
		PATH="$PATH:$VBOOT_TOOLS_PATH"
	fi

	if [ -z "$VBOOT_KEYS_PATH" ]
	then
		if ! [ -z "$VBOOT_TOOLS_PATH" ] && [ -d "$VBOOT_TOOLS_PATH/devkeys" ]
		then
			VBOOT_KEYS_PATH="$VBOOT_TOOLS_PATH/devkeys"
		else
			VBOOT_KEYS_PATH="/usr/share/vboot/devkeys"
		fi
	fi
}

cros_kernel_install() {
	local action=$1
	local storage_path=$2
	local kernel_image_path=$3
	local kernel_modules_path=$3

	set -e

	setup "$@"

	if [ -z "$action" ] || [ -z "$storage_path" ] || [ -z "$kernel_image_path" ] || [ -z "$kernel_modules_path" ]
	then
		usage
		exit 1
	fi

	case $action in
		"backup")
			requirements "cgpt"
			backup "$storage_path" "$kernel_image_path"
			;;
		"image")
			requirements "cgpt"
			image "$storage_path" "$kernel_image_path"
			;;
		"modules")
			requirements "cgpt"
			modules "$storage_path" "$kernel_modules_path"
			;;
		*)
			usage
			exit 1
			;;
	esac
}

cros_kernel_install "$@"
